With the proliferation of mobile devices such as smartphones, mobile phones, and tablets in recent years, the opportunities to use these mobile devices in public places such as inside trains has increased.
Mobile devices are small and easily lost. A password (or passcode) is usually set in order to lock the screen of mobile devices. In order to provide greater password security, these passwords are usually long (a combination of six or more alphanumeric characters).
The user of a mobile device can use all of the functions once the mobile device has been unlocked using this password.
In recent years, employees have been bringing their personal information terminals to work and using them to conduct company business as part of a policy known as “bring your own device” or BYOD. With the introduction of BYOD, employees do not have to possess multiple devices and can use a device with which they are already familiar. However, certain functions used at the workplace and websites that can be accessed at the workplace have to be restricted, and access to company data outside of the office must be limited. Therefore, in order to provide greater password security in BYOD devices, these passwords are usually long (for example, a combination of six or more alphanumeric characters).
Patent Literature 1 describes a method for providing simple access control to various resources in electronic file devices used to handle shared files using a user-friendly interface establishing a positional relationship between icons and windows (paragraph 0010).
Patent Literature 2 describes a mobile terminal which includes a screen unlocking means that unlocks the terminal touch screen when a particular operation is performed using contact information icons (paragraph 0012).
Patent Literature 3 describes a method for unlocking a device with a touch screen display which includes the following steps: sensing touch screen input; determining whether or not the input is a request to unlock the device; determining whether or not the input is related to a device function; unlocking the device when the input is a request to unlock the device; and loading an application related to the input when the input is related to a device function (claim 1).
Patent Literature 4 describes a method executed by a computer which includes the steps of: receiving selection input including one or more gestures on the touch screen of a computing device; responding to the selection input by selecting a first lock screen pane among a plurality of lock screen panes in a user interface with lock screens for multiple access levels, each lock window pane being associated with a different access level, and each access level corresponding to a different function in the computing device; and responding to the selection by displaying the first lock screen pane (claim 1).
Patent Literature 5 describes a user verification device including an access granting means which grants access in response to an evaluation of password weakness (claim 1).
Patent Literature 6 describes a control program for controlling the executability of a processing request when an ID and predetermined authorization information related to the ID have been entered into a computer, and the processing in the processing request is processing permitted under the authorization information (claim 1).
Patent Literature 7 describes a verification program for logging into a system on the basis of identification information and password information, the verification program executing in a computer a receiving means for receiving identification information and password information, a retrieval means for retrieving authorization information corresponding to the password from the identification information and password information, and an output means for outputting the identification information and authorization information (claim 1).
Patent Literature 8 describes an information processing device including an input means for inputting a password, a password storing means for storing a plurality of passwords, a usage status detecting means for detecting usage status, a password selecting means for selecting a password corresponding to the usage status detected by the usage status detecting means from among the plurality of passwords stored in the password storing means, a password comparing means for comparing the password inputted using the input means to the password selected by the password selecting means, and a user verifying means for verifying an authorized user when the comparison results from the password comparing means match (claim 1).
Patent Literature 9 describes an information processing device with a locking function that restricts user operations in which the information processing device includes a lock setting unit which shifts the information processing device into the locked state when a user operation has not been inputted over a predetermined period of time, an unlocking unit which unlocks the device in response to the input of a predetermined first password, and a changing means for changing the number of characters that have to be inputted from the first password to unlock the device in response to the usage status of the information processing device (claim 1).
Patent Literature 10 describes a technique for displaying information related to the complexity of a user-registered password in a manner recognizable to the user (paragraph 0001).